Novel process for preparing carbonic ester and aryl methylamine and green co-production technology

Abstract

The invention relates to the field of new material chemicals, and discloses a technology for preparing carbonic ester and aryl methylamine through two-step reaction green co-production by taking carbamate and aryl methyl halogenated hydrocarbon as initial raw materials for the first time. The whole process is simple and convenient to operate, generation of organic waste is avoided, atom economy is achieved, and conversion from low-cost raw materials to high-added-value products is achieved.

Description

[Technical field]

[0001] The present invention relates to the field of new material chemicals, and in particular to a new method technology for green co-production of carbonate and aromatic methylamine by using carbamate and aromatic methyl halogenated hydrocarbon as starting materials through a two-step reaction. [Background technology]

[0002] Carbonate is a new generation of basic green chemical raw materials with excellent performance. The most typical dimethyl carbonate (DMC) can be used in new energy battery electrolytes, gasoline additives, paint solvents, and carbonate resin manufacturing. With the enrichment of carbonate products and the continuous development of technology in recent years, especially the growing demand for green coatings and new energy battery systems, carbonate compounds have seen rapid capacity expansion. New cost-reducing and efficiency-enhancing, green and environmentally friendly production process technologies are major industrial research topics that the industry is striving for.

[0003] The traditional process for preparing carbonate substances is the condensation reaction of phosgene and alcohol; the current mainstream process is to prepare them by transesterification of ethylene carbonate with different alcohols; the above process is harsh and has poor selectivity. The preparation of carbonates by direct esterification and dehydration of alcohols and carbon dioxide is a very challenging technical route; currently, it is necessary to add catalysts that are not common in the market and harsh reaction conditions; a recent industry review reviewed various catalysts or promoter systems in detail (Energies2022,15,5133), but they generally have insufficient reaction activity or are prone to deactivation and failure, and the conversion rate and product yield are low. Urea is used as the starting material and reacts with ethylene glycol to first generate an ethylene carbonate intermediate, which still requires the use of zinc catalysts and has the above-mentioned problems. Therefore, it is difficult to achieve industrialization.

[0004] On the other hand, the traditional process for preparing aromatic methylamines, such as benzylamine, is produced by nucleophilic substitution and hydrolysis reaction between benzyl chloride and urotropine under acid catalysis; and urotropine is highly flammable. Benzylamine can also be prepared by aminolysis reaction between benzyl chloride and ammonia; but this process requires the addition of multiple equivalents of ammonia. The requirements of both processes are very demanding.

[0005] In our previous applications, we have disclosed the use of simple and readily available raw materials, namely, hydrocarbon carbonate salts and aromatic methyl halides as starting materials through a two-step reaction to achieve green co-production of carbonates and aromatic methyl alcohols, thus reducing costs and increasing efficiency.

[0006] In this application, we have realized for the first time the technology of green co-production of carbonate and aromatic methylamine using carbamate and aromatic methyl halogenated hydrocarbon as starting materials through two-step reaction. Among them, the raw material carbamate can be directly produced by the reaction of urea and alcohol without the need for a catalyst. The whole process is simple to operate and avoids the generation of organic waste, realizing the transformation from low-cost raw materials to high-value-added products, and practicing the beneficial effect of reducing costs and increasing efficiency. [Summary of the invention]

[0007]

[0008] The present application found that, as shown in reaction formula (I), a nucleophilic substitution reaction occurs between carbamate A and halogenated methyl aromatic hydrocarbon B under reaction condition 1 to generate an intermediate arylmethylamino carbonate C; and then an alcoholysis reaction continues under reaction condition 2 to generate a carbonate product D and an arylmethylamine product E.

[0009] The reaction conditions condition 1 and condition 2 are independent of each other and are at least one of a solvent, a temperature and an additive.

[0010] Wherein, R1 or R3 are independently a branched or straight chain aliphatic (hetero) hydrocarbon group containing 1 to 24 carbon atoms, or a (hetero) aromatic hydrocarbon group containing 4 to 24 carbon atoms; R2 is H, or a branched or straight chain aliphatic (hetero) hydrocarbon group containing 1 to 24 carbon atoms; X is a halogen F, Cl, Br or I. Preferably, R1 or R3 are independently methyl, ethyl, propyl, butyl, allyl, benzyl, phenyl, naphthyl, hexadecyl; R2 is H, F, Cl, Br, methyl, ethyl, propyl, butyl, allyl, benzyl, phenyl, naphthyl, hexadecyl, or a mixed multiple substituent of the above groups; X is Cl or Br.

[0011] The solvent is selected from at least one of (sub)sulfone, amide, ether, ester, alcohol, ketone, nitrile, carbonate, ionic liquid, and supercritical carbon dioxide. Preferably, the solvent is acetonitrile, methanol, ethanol, propanol, butanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, dimethyl sulfone, cyclopentane, methylene chloride, ethylene dichloride, chloroform, carbon tetrachloride, dimethyl carbonate, diethyl carbonate, ethylene carbonate, benzene, toluene, xylene, chlorobenzene, dichlorobenzene, nitrobenzene, dioxane, tetrahydrofuran, methyl tert-butyl ether, ethylene glycol dimethyl ether, anisole, N,N-dimethylformamide, N,N-dimethylacetamide, at least one or more mixed solvents.

[0012] The temperature is 0°C-400°C; preferably, the temperature is 20°C-200°C.

[0013] The additive refers to a reaction promoter, a synergist, a catalyst, an inhibitor, an oxidant, a reducing agent and / or a functional aid. Based on the molar amount of the reaction raw materials, the amount of the additive used is a catalytic amount or an equivalent or an over equivalent (0-100 equivalents). Preferably, in condition 1, the additive is one of NaH, CaH2, CaC2, BuLi, LDA, LiHMDS, NaHMDS, KHMDS, Li2CO3, Na2CO3, K2CO3, Cs2CO3, LiOH, NaOH, and KOH; based on the molar amount of carbamate A, the amount of the additive used is 0.5 equivalent to 2 equivalents. In condition 2, the additive is one of Li2CO3, Na2CO3, K2CO3, and Cs2CO3; still based on the molar amount of carbamate A, the amount of the additive used is 0 equivalent to 0.5 equivalent.

[0014] Through the technology disclosed in the present invention, the following exemplary but non-limiting carbonate compounds and the corresponding aromatic methylamines can be prepared in high yields:

[0015]

[0016] The gist of the present invention is further explained below with reference to specific embodiments. [Specific implementation method]

[0017] Embodiment 1:

[0018]

[0019] Dissolve methyl carbamate (1.50 g, 20 mmol) in DMF (20 mL) at room temperature, then add CaH2 (0.51 g, 12 mmol), stir for a few minutes, and then add benzyl bromide (3.42 g, 20 mmol). React in a 90°C oil bath for 16 hours. After cooling to room temperature, filter, and then remove the solvent by reduced pressure distillation. The crude product is directly used for the next step reaction.

[0020] The crude product of the first step reaction was dissolved in methanol (20 mL), transferred to a hydrothermal synthesis reactor, and a catalytic equivalent of sodium carbonate (0.21 g, 2 mmol) was added, and then sealed. The temperature was raised to 55°C for reaction for 12 hours. After cooling to room temperature, the reactor cover was opened, biphenyl was added as an internal standard, and then sampling was performed to monitor the reaction. By gas chromatography (using biphenyl as an internal standard to make a standard curve), it was found that the content of the target product dimethyl carbonate in the reaction solution was 1.12 g (12.4 mmol), and the total yield of the two steps was 62%; the content of benzylamine was 1.39 g (13 mmol), and the total yield of the two steps was 65%.

[0021] Embodiment 2:

[0022]

[0023] Dissolve methyl carbamate (1.50 g, 20 mmol) in sulfolane (20 mL) at room temperature, then add cesium carbonate (3.26 g, 10 mmol), stir for a few minutes, and then add benzyl chloride (3.42 g, 20 mmol). React in a 150°C oil bath for 16 hours. After cooling to room temperature, filter, and then remove the solvent by reduced pressure distillation. The crude product is directly used for the next step reaction.

[0024] The crude product of the first step reaction was dissolved in ethanol (20 mL), transferred to a Schlenk reaction bottle, and a catalytic equivalent of sodium hydroxide (80 mg, 2 mmol) was added, and then sealed. The temperature was raised to 80°C for reaction for 12 hours. After cooling to room temperature, the bottle stopper was opened, biphenyl was added as an internal standard, and then sampling was performed to monitor the reaction. By gas chromatography (using biphenyl as an internal standard to make a standard curve), it was found that the content of the target product methyl ethyl carbonate in the reaction solution was 1.02 g (9.8 mmol), and the total yield of the two steps was 49%; the content of benzylamine was 1.16 g (10.8 mmol), and the total yield of the two steps was 54%.

[0025] Embodiment 3:

[0026]

[0027] Dissolve ethyl carbamate (1.78 g, 20 mmol) in NMP (20 mL) at room temperature, then add potassium carbonate (1.38 g, 10 mmol), stir for a few minutes, and then add p-methoxybenzyl bromide (4.02 g, 20 mmol). React in an oil bath at 170°C for 16 hours. After cooling to room temperature, use it directly in the next step without any treatment.

[0028] Add ethanol (30mL) to the first step reaction solution, transfer to a hydrothermal synthesis reactor, and then seal it. Heat to 80°C for 12 hours. After cooling to room temperature, open the reactor cover, add biphenyl as an internal standard, and then take samples to monitor the reaction. By gas chromatography (using biphenyl as an internal standard to make a standard curve), it is found that the content of the target product diethyl carbonate in the reaction solution is 1.42g (12mmol), and the total yield of the two steps is 60%; the content of p-methoxybenzylamine is 1.70g (12.4mmol), and the total yield of the two steps is 62%.

[0029] It should be emphasized that the above embodiments are merely illustrative and not restrictive. Based on the disclosure of this application, any adjustment or change in reaction conditions or parameters that may be commonly adopted by practitioners will not deviate from the gist of the present invention. The scope of protection of this patent shall be based on the relevant rights record items.

Claims

1. A new process and green co-production technology for preparing carbonates and aromatic methylamines. As shown in reaction formula (I), carbamate A and halogenated methyl aromatic hydrocarbon B undergo nucleophilic substitution reaction under reaction condition 1 to prepare intermediate aromatic methylcarbamate C; intermediate C continues to undergo alcoholysis reaction under reaction condition 2 to prepare carbonate product D and aromatic methylamine product E. in, R1 and R3 are independently a branched or straight chain aliphatic (hetero) hydrocarbon group containing 1 to 24 carbon atoms, or a (hetero) aromatic hydrocarbon group containing 4 to 24 carbon atoms. R2 is H, or a branched or straight chain aliphatic (hetero) hydrocarbon group containing 1 to 24 carbon atoms. X is a halogen F, Cl, Br or I. The reaction conditions condition 1 and condition 2 are independent of each other and are at least one of a solvent, a temperature and an additive.

2. According to claim 1, the solvent is selected from at least one of (oxy)sulfones, amides, ethers, esters, alcohols, ketones, nitriles, carbonates, ionic liquids, and supercritical carbon dioxide. The temperature is 0°C-400°C. The additives are reaction accelerators, synergists, catalysts, polymerization inhibitors, oxidants, reducing agents and / or functional additives.

3. According to claim 1, the process disclosed in the present invention can be used to prepare but is not limited to the following compounds:

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